Axions that solve the strong CP problem but are heavier than the canonical QCD axion have been explored since long and revived in the last years [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}, [11]}, [12]}, [13]}, [14]}, [15]}, [16]}, [17]}. In contrast, solutions to the strong CP problem with lighter axions were uncharted territory until very recently.
